Backpack



Fig. 3.1 is a front view of a backpack embodying the new design;

Fig. 3.2 is a right-side perspective view thereof;

Fig. 3.3 is a left-side perspective view thereof; and

Fig. 3.4 is a rear view thereof.

The broken line showing of portions of the backpack is for the purpose of illustrating stitching and forms no part of the claimed design. 

CLAIM The ornamental design for backpack, as shown and described. 